[FR]: 'No grid export'

[wonko]

Description

We have, when the energy price is negative, a penalty when you export electricity to the grid. As long as the battery isn't fully charged, excess PV energy is sent to the battery.

Is there a mode in "Modbus Power Control" where excess PV power isn't sent to the grid, but "discarded"? The only way I currently can do this is to turn of the inverter completely, but the side-effect is that we then use grid-energy for the house load, while there actually is PV power.

Suggested Solution

No idea - either some documentation or a good example on this...

Alternatives

Turning the inverter off. If the energy price is significantly negative, this has no downside. Due to the way grid export is calculated when the price is close to 0, this comes at a cost.

Additional Context

Solax inverter, Gen4, already using modbus power control for charging/discharging etc.

[romankysely]

You can use settings from integration whe you setup SolaX Export Control User Limit=0 for export energy to the grid. If the value of the electricity is positive you can return value of limit back. All proces is easy to handle automaticly via Automations if you will be checking price from supplaier continously.
Example of YAML:
alias: Nastavení Solax Export Control Limit
description: >-
Automatizace pro nastavení Solax export control limit na základě ceny
produkce.
trigger:

• platform: state
  entity_id: sensor.current_production_price_consumption_with_nano_czk_kwh
  action:
• choose:
  • conditions:
    • condition: template
      value_template: >-
      {{
      states('sensor.current_production_price_consumption_with_nano_czk_kwh')
      | float <= 0 }}
      sequence:
    • service: number.set_value
      target:
      entity_id: number.solax_export_control_user_limit
      data:
      value: 0
  • conditions:
    • condition: template
      value_template: >-
      {{
      states('sensor.current_production_price_consumption_with_nano_czk_kwh')
      | float > 0 }}
      sequence:
    • service: number.set_value
      target:
      entity_id: number.solax_export_control_user_limit
      data:
      value: "15000"
      mode: single

[wonko]

Thanks @romankysely, I didn't know this setting. I assume this writes to the EEPROM, thus should we avoid setting this too much? Is there a equal setting or mode using the remote power control?

[romankysely]

Yes I suppouse there is EEPROM write unfortunately but I did not find any relevant option via Remotecontrol. May be change YAML code to write to registere after minus/plus state not each hour.

[wonko]

Setting it only once would indeed be better then (and easy to do, so that's not really a problem).

I'm using the remote power control a lot, and I was looking for this functionally there as well. In the wiki, there's this fragment (last entry of https://github.com/wills106/homeassistant-solax-modbus/wiki/Modbus-Power-Control-(remotecontrol-power)#parameter-entities):

remotecontrol_export_limit: (ATTENTION: not working as intended - removed) In Enabled Power Control mode and Enabled Battery Control mode, the Grid import or export level can vary with the house load and PV power. This parameter makes it possible to perform 'peak shaving', so that the export power can be limited to a defined max value. In Enabled Grid Control mode, this parameter has no sense as the export level is fixed. In this case, this parameter must be set to a high value.

The export-limit sounds like what I'd need, but unfortunately this isn't working it seems. Maybe someone knows what's wrong with it, or if it needs testing in some kind.

Anyhow, thanks for the answer, I'll use this for now.

[romankysely]

We have about 1.000.000 hits to EEPROM I suppose :-))
I have another problem. I have setup Setting/Advanced/Export Control/User Value = 15000W. I can not to rise to 22000W. Maybe there is limit on inverter. I have 2 invertors 12kW each. Master has = 15000 and Slave = 0W set. I suppose there is one value for tandem for Export Limit. Integration not allow me change value more than 15000. Any idea?

[wonko]

Seems like a bit off-topic for this feature request, but I guess you could take a look at https://github.com/wills106/homeassistant-solax-modbus/blob/main/custom_components/solax_modbus/plugin_solax.py#L329 - seems like the limits are defined over there. I only have a single 6kW Gen4 setup, so no help from my side.

[romankysely]

Thx for interesting source of info.
Back to topic "prohibit export":
First I have to correct myself - not 1.000.000 writes to EEPROM alow but 100.000 only (source https://homeassistant-solax-modbus.readthedocs.io/en/latest/solax-G4-operation-modes/).
I have read documentation regarding Remotecontrol (as you mentioned - thx). I am little bit confuse with this part: "remotecontrol_export_limit: (ATTENTION: not working as intended - removed)". Does not work at all or is it replaced by some mode?
I supouse all of us who has a risk of penalty for export energy out must automaticly manage it. So how do you all guys resolve it? Everybody do not care to write to EEPROM? Or any other idea how to manage it?
PS: BTW I resolved my question regarding Maximum Export Limit there #858

[wonko]

Closing this, as the "solax_export_control_user_limit" is the parameter needed to limit the export towards the grid.